1. Field of the Invention
The present invention is directed to a material handling system having reduced installation, modification and maintenance costs, and more specifically to a friction drive conveyor system having independent and intelligent drive controllers for controlling friction drive motors, and wherein the drive controllers may communicate routing information and other data wirelessly with each other.
2. Discussion
Material handling systems and installed conveyor systems are used in a variety of manufacturing and material handling settings to move workpieces and other loads from point to point. Each setting and each type of workpiece or load transported may have different requirements and a wide variety of conveyor styles and carrier styles exist to fulfill these requirements.
One commonly used material handling system used in manufacturing settings for transporting workpieces and in some material handling settings for transferring loads is a friction drive conveyor system. Friction drive conveyor systems are capable of handling a variety of workpiece or load sizes, and many are configured to even carry vehicles from point to point in a manufacturing setting. While most friction drive systems include a rail or track from which the workpiece or load carrier hangs from or rides upon, such as the illustrate monorail, some friction drive conveyor systems have been formed without tracks or rails.
While the manufacturing costs for forming the individual components of a friction drive conveyor system, including material costs, may be formidable, one major expense of the final cost is the installation expense. A friction drive conveyor system traditionally includes many drive motors in direct electrical communication with a central controller for controlling the movement of a workpiece carrier, and receiving tracking information. In fact, in many friction drive systems, the system may be configured to have a friction drive motor in contact at all times with each workpiece carrier to control the movement of the workpiece carrier, including stops, accelerations, and routing of the workpiece carrier. This constant contact of at least one friction drive motor ensures constant control of the workpiece carrier in settings where the workpiece carriers may pass along the material handling path with gaps between. However, each friction drive is wired to the central controller creating high installation expenses due to the materials and installation time required.
In new facilities, this installation may be simplified by running the wiring before the floor is installed, typically poured concrete. However, this method makes any future changes to the configuration of the system difficult. In existing facilities, the wiring routes and installation of wiring may be even more expensive and time consuming, requiring use of conduit and wire runs, drilling through floors and other stationary members and ensuring that the wiring is protected from damage. Also, due to the size, configuration and at times the manufacturing operations being performed, it typically is difficult to reliably have each drive controller directly communicate wirelessly regarding sensor information to a central controller and in turn directly receive commands from a central controller. For example, a conveyor path may pass around massive machinery, through tunnels, past operations that interfere with wireless signals, and stretch along its complete length for long distances, all of which negatively effect reliable wireless communication for each drive motor with the central controller. Therefore, until now no system reliably existed which also allowed reduced installation costs by the elimination of wired controls between the central controller and each drive motor.